SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8df5393c42cab98ac4c6a76c68cb5d3130b5fbf8c1c378dd84b40f5ee450a030' 
  AND token = 'bDo88FWK/Vv8FKCXDmJhiI+NLZMvPIlQBNk4VYvxwEc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}